CrunchBase is a freely available database of start-ups, entrepreneurs, and investors that can be edited by anyone. Not surprisingly, it is typically more up-to-date than traditional pay-to-play company databases such as Hoover's, but tends to have less detail and might be slightly less reliable, although that is changing by the minute. The typical use case is when doing research on which tech startups exist out there and are likely to disrupt a given market.